This invention relates to a method of inspecting semi-manufactured articles after the ILB (Inner Lead Bonding) process which is the process for manufacturing TAB (Tape Automated Bonding) products, and an apparatus for inspecting the same, and more particularly to a method and an apparatus used for automated inspection of the bonding state of an inner lead bonding by observation of its appearance.
In accordance with the TAB system, inner leads of a carrier tape are aligned with a plurality of electrode bumps or projected-connection electrodes formed on an IC pellet. Then, the inner lead bonding process for simultaneous connection is carried out. In the prior conventional art, the judgment arts whether or not the bonding or connecting state between bumps and inner leads is good was conducted by a visual human inspection, using a stereoscopic-microscope.
In accordance with this method, a visual inspection operator inspected the inner lead surface in the vicinity of the bonding portion of the inner lead to subjectively judge, relying on the operator's training and experience. If the surface is shining brightly, the bonding state is judged to be acceptable, If not, the bonding state is judged unacceptable".
Since the objective judgment as to whether or not bonding state is good cannot be so conducted. There may be disagreement between operators, or disagreement due to a lapse of time even for the same operator. As a result, the quality varied. Further, in a visual test, there is high possibility that oversight, misperception, etc. may occur. Accordingly, the criteria for judgment may change or an artificial error may occur. On the other hand, although automation of the manufacturing process may be required, conventional subjective testing methods cannot cope with automation.